Incorporated herein is a computer program listing microfiche appendix of source code used to access, modify and monitor control signals sent between a host computer and a peripheral device such as an ion implanter, according to the present invention. Copyright, 1993, Advanced Micro Devices, Inc. A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the "microfiche appendix", as it appears in the Patent and Trademark Office file or records, but otherwise reserves all copyright rights whatsoever.
1. Field of the Invention
This invention relates to semiconductor manufacturing and more particular to an ion implant device having programmable and graphical user interface.
2. Background of the Relevant Art
Ion implantation devices, or ion implanters, are well known. A primary function of an ion implanter is to provide an ion beam with sufficient energy to penetrate a solid surface. Ion implanters are commonly used in the semiconductor industry to introduce impurities or dopants into the solid semiconductor surface. The depth in which ions are introduced into the semiconductor increases as acceleration voltage of the implanter increases. Moreover, the total number of ions injected is proportional to the beam current and implant time of the implanter. For singly charged ions, each ion has a charge q of one electron, which relates to 1.6.times.10.sup.-19 coulombs. Thus, if .phi. ions per cm.sup.2 (or dose) are to implanted for a wafer of area A cm.sup.2, qA.phi. coulombs are required. If the implant is to be accomplished in t seconds, qA.phi./t coulombs per second are needed. Since current in amperes is coulombs per second, the beam current I can be expressed as follows: ##EQU1##
"Implant parameters" as defined herein is any setting or resulting implant value which can be achieved by an ion implant device. Implant parameters can be measured directly by the implanter or indirectly from the resultant semiconductor surface. Implant parameters include ion beam current, ion implant dose, ion source energy, ion acceleration voltage (or implant depth), etc. Depending upon the desired application, implant parameters can vary in order to achieve a necessary outcome. For example, MOS threshold adjust does not require as large an implant dose as bipolar bases or CMOS wells. Moreover, resistors, while requiring a larger implant dose than MOS threshold adjust, does not require as large a dose as embedded oxide and nitride areas. Not only does implant dose vary depending upon the target application, but implant depth (range) may also vary depending upon the application. Still further, impurity ions of different species have dissimilar atomic mass. Fluctuation in atomic mass (i.e., selection of ionic doping species) requires a corresponding change in implant parameters. Even still further, modern lithography processing often utilizes shallow junction diffusion thereby requiring close tolerances in implant depth.
Knowing the importance in maintaining fairly precise implant parameters, it is necessary that the parameters be closely monitored and that the parameters be "set" into the implanter with minimum error. Conventional implanters often utilize a control panel configured within or upon the implanter housing. The control panel employs a series of switches and light emitting diodes (LEDs). The switches allow the operator to make various parameter setting upon the implanter. LEDs indicate to the operator that the settings have been made. For example, a switch or dial placed upon the implanter can allow the operator to adjust beam current in milliamperes. The resulting LED readout will indicate and hopefully verify the amperes magnitude presently selected.
Each time the implanter processes a wafer lot of dissimilar technology from the previous lot, the implant parameters must be changed. For example, a dynamic random access memory (DRAM) wafer lot utilizing shallow junction depths and possible threshold adjust requires change in implant parameters before an analog, bipolar wafer lot of deeper junction depths is processed. Change in implant parameter between wafer lots can easily lend itself to operator error. Further, frequent verification of implanter settings is required in order to ensure proper operation. It may be necessary to actuate numerous switches and dials before the subsequent wafer lot is loaded. The operator may inadvertently fail to make one or more of the necessary changes or may fail to check or monitor the implanter to ensure the implanter has correctly made the change. The switches or LEDs may sometimes malfunction causing the operator to sense that a change was made; however, examination of the wafer may indicate that the change was not made or was made out of specification.